This invention relates to a vibration isolator and more particularly but not by way of limitation to an active vibration isolator used in conjunction with a spring biasing means and a solenoid with a control system to operate the solenoid so the solenoid shaft moves in an equal but opposite direction to the vibration placed on the spring.
Heretofore, in a dynamic environment such as encountered by an aircraft, payload stablization requires the removal of the vehicle dynamics in the form of pitch, yaw and roll and the effects of vibration along each of these axis. In a non-vibrational dynamic environment, it is difficult to stablize a payload because of the lag in the measurement, control, and stablization of the system. This is caused by the time required for a sensor such as an accelerometer to measure a force or movement, the control system to interpret the movement or force, and the time required for some stablization system such as a torquer to react to the commands issued by the control system.
In the real world the ability of a control system with its train of measurements and action devices to control unexpected movement is degraded by vibration in the pitch, yaw and roll direction. These vibrations and unexpected impulses are caused by wind gusts, engine operation and other external and internal sources. Some vibration and impulses are eliminated by the use of shock mounts or other passive devices. The remaining vibrations which can only be partially eliminated by the control system must be tolerated by the payload.
In U.S. Pat. No. 2,964,272 to Olson, U.S. Pat. No. 3,216,679 to Curwen, U.S. Pat. No. 3,464,657 to Bullard, U.S. Pat. No. 3,606,233 to Schraton et al, U.S. Pat. No. 3,952,979 to Hansen and U.S. Pat. No. 4,033,541 to Malueg various types of active and passive vibration isolators are shown for supporting different types of equipment for isolating different types of vibration. None of these vibration isolators specifically disclose the unique feature of the subject active vibration isolator which in real time will remove vibrations, impulses and other low level pitch, yaw and roll motions before they are transferred to the payload.